This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. To study protection effects of an HIV Tat specific intracellular antibody against viral infection, adult rhesus monkeys (Macaca mulatta) served as a model for gene therapy experiments against HIV-1-infecton and the development of AIDS. Following re-infusion of ex-vivo MLV transduced CD4+-enriched (CD8-depleted) cells, expressing an irrelevant intrabody (A3H5-Flag) and a therapeutic anti-tat sFv intrabody (hutat2-HA), animals were challenged intravenously with a pathogenic SHIV strain. Survival of transduced CD4+ cells and gene marking of the A3H5 or sFv hutat2 transgenes were analyzed, respectively, by FACS and real-time PCR. Levels of SHIV plasma RNA and CD4 counts in the treated macaques were also monitored. In addition, CTLs and/or antibodies against the A3H5 or hutat2 intrabodies will also be monitored. Axillary lymph nodes will be sampled serially and evaluated histopathologic for LN architecture. Finally, transduced cells will also be identified by IF for intracellular A3H5 or sFvhutat2 expression.